Automatic regulator for electric systems



Aug. 10 1926.

- H. TERHORST AUTOMATIC REGULATOR FOR ELECTRIC sys'rzms Filed April 12,1924 A TTORNEY.

lator which will respon Patented Aug. 10,- 1926.

UNITED STATES PATENT OFFICE.

'mvmr TEBHOBST, 0] DdNNYBBOOK, NORTH DAKOTA.

AUTOMATIC REGULATOR FOR ELECTRIC SYSTEMS.

Application fled mi, 18, 1994. mm in. 160,013;-

This invention pertains to the re lation of generator battery electriclighting and power circuits.

One object ofthe present invention is the These and other objects andadvantages will ap ear from the following description of an illustrativeembodiment of the present invention.

In. the accompanying drawings:

Figure 1 is a perspective view of a regulator constructed in ac cordancewith the present invention, partsbeing broken away for clearness.

Figure 2 is a diagrammatic view of a generator battery li hting s stemillustrating a use to which t e regu ator of Figure 1 may be applied.

The system illustrated in Figure 2 comrises two main conductors 10 and11 leading from the generator 12 to the lamps 13 and connected by abranch conductor 14 in which a storage battery 15 is connected. One ofthe main conductors 11 is provided with 'the usual automatic cut outswitch 16 between the generator and battery. The generator is adapted tobe driven at variable speed from the caraxle, windmill or other powersource. The shunt field 17 of the generator is connected across the twoconductors 10 and 11 through leads 18 and 18' and through variableresistance 19 controlled by a regulator preferably such as will now bedescribed.

The regulator shown, particularly in Figure 1, comprises an arm 20normally balanced in substantially horizontal -position but free toswing about a substantially horizontal axis. The arm 20 is shownprovided with a pair of fulcrum points 21 each resting upon a bearingblock 22 of hard, pieferably insulating, material, secured in a edhorizontal rail 23 constituting a part of asubstantially rectangularframe 24. The arm" carries a series ofcontact points 25 in electricalcontact therewith and each depending therefrom into one of a series ofmercury cups 26 formed in a block 27 of insulating material, This blockis ri 'dly supported by and between the fixed -raiTs 23 and is rov dedin its base with a series of biii ing posts'28 each in electricalcontact with the mercury in one of the cups 26. The several bindingposts 28 are connected through leads 31 with the resistance 19 atsuccessive in;

tervals thereon.

The mercury in the several cups is at a uniform level and the severalcontact points 25 are of different graduated len hs so that,

as the arm 20 is swung upwar ly from its normal horizontal position, thepoints 25 are successively withdrawn out of contact with the mercury inthe corresponding cups. The arrangement is such that when the arm is inits normal horizontal position with all the points 25 in electricalcontact with the mercury in the corresponding cups, the resistance 19 isshort-circuited out of the generator field circuit and generator volt-'age is at a maximum, but as the arm moves from horizontal position so asto'withdraw the points 25 successively out of the bodies of mercurysuccessive increments ofthe resistance 19 are returned to the fieldcircuit to reduce the generator voltage,

It might be pointed out here that with all of the points 25 partiallyimmersedin the mercury in the several cups, the arm 20 is partiallysupported b the buoyant effect of the mercury upon t 'e points, but asthe arm is swung upwardly this buoyant effect is reduced. so that thetorque required to swing the arm upwardl becomes reater as the armswings upwar ly. In or er to insure a smooth action of the armagainstthe inertia effect thereof and of the parts carried therebyadashpot of appropriate design is preferably provided. In this instance,the dashpot em loyed comprises a dasher 32 immersed in a ody of liquid33, preferably oil, contained in an appropriate chamber 34.

The dasher is supported by a rod 35 extending through the top of thechamber and pivotally secured to a rear extension 36 of the arm 20. Thearm 20 carries a polarized magnet in the form of a coil 37 wrapped abouta post 37" fixed in vertical position on thearm so that the axisthereofis normal to and intersects the horizontal axis about which thearm rocks. This coil'is connected across the generatcr circuit. Oneterminal thereof is connected through a lead 38 to a contact point 39carried by the arm and insulated therefrom. This contact point is inpermanent contact with the mercury in a cup 40 trical contact with themercury in cup 26".

By thus connecting the leads 38 and 43 to parts carried by the arm 20,rather than to Med points in the system, movement of the arm is nothindered by the otherwise necessary flexing of the leads, and the arm,coil, and leads are removable as a unit from the rest of the mechanism.

The arm 20 is regulated and controlled by the coil 37 which reacts underthe influence of the magnetic field which in turn responds to conditionsin the main circuit. In the regulator shown, a coil 44 is wrapped aboutthe main frame 24 with its axis normal to and intersecting both the axisof coil 37 and the horizontal axis about which the arm 20 swings. Coil44 is connected in the branch conductor 14 in series with the battery 15so as to respond to the current flow between the generator and battery.The arrangement is such that while the battery is being charged themagnet field set up by the current passin through coil 44 reacts uponthe magnetic fie d of t e coil 37 to maintain the coil 37 andconsequently the arm .20 in a slightly tilted position. With everychange in the battery charging rate there is a correspondmg chan in thestrength of the field of the coil 44 w ich results in a variation in theposition of the coil. 37 and arm 20. Thus the amount of resistance inthe shunt field of the generator. is made to vary directly as the atterycharging rate so that as the charging rate tends-to increase abovenormal, genera tor voltage immediately decreases, and vice versa, withthe result that the current flow to the battery is automaticallymaintaine at a definite normal rate. Since the efiect of gravity on thearm 20 m any of its tilted positions varies directly as the cosine ofthe angle of inclinationof the arm, and since the magnetic pull of coil44' upon coil 37 varies directly as the cosine of the angle ofinclination of the coil 37, and smce t ese angles are always equal, itnecessarily follows that the relative effectiveness of the force ofgravity, tending to return the arm 20 to horizontal position, and of theflows from magnetic pull between the coils 37 and 44, tending to tiltthe arm, are substantially the same in all positions of the arm. Thevariations in the magnetic strength of coil 44 are thus balanced solelyagainst the variations in the buoyant effect of the mercury upon thecontact points 21. The arm 20 will thus respond to very slight changesin the current passing through coil 44. It will also be noted that thecoil 44 is free from iron so that la and hysteresis losses are avoided.

Anot er coil 45 is wra ped about coil 44 and similarly disposed reatively to the coil 37. This coil 45 is connected at one end through alead 46 to a fixed contact 47 through which it'is connected to the mainconductor 11 when the cut-out switch 16 is closed. The other end of coil45 is connectible to the other main conductor 10 through a lead 48 andeither of two switches 49 or 50. Switch 49 is arranged to closeautomatically when the battery 15 has been fully charged andfor thispurpose is placed under the control of an appropriate device whichresponds to the condition of charge of the battery. In the system shown,this device is typified by an ampere-hour meter 51, connected in thebranch conductor 14 in series with the battery and having a ointer 52which when the battery is fully c arged strikes and closes the switch49. The other switch 50 is a manually operated switch ordinarily placedat a distance from the regulator. This switch is operable to close theshunt circuit through the coil 45 before the battery is fully chargedand cooperates with a variable resistance 53 in series with the coil45,by which the strength of the coil may be regulated.

The 0 eration of the system will now be described As the generator 12comes up to s eed the cut-out switch 16 automaticaly c oses in the usualmanner. Assuming that the battery 15 is not fully charged, current thegenerator through the branch conductor 14, coil 44, and meter 51 to thebattery to charge the battery. Under these conditions, coil 44 actingupon coil 37 controls the arm 20 of the regulator to maintain thecharging current substantially constant as hereinabove described. Whenthe battery has been fully charged, as indicated by the meter 51, thepointer 52 thereof strikes and closes the switch 49, thereby connectingthc'coil 45 across the generator circuit. The coil 45 thus excitedexerts a magnetic pull upon the the arm 20 so that an increasedresistance is thrown into the generator field circuit to reducegenerator voltage to such an extent as to cause the generator to floaton the batter The fact that the coil 37, as well as coi 45, is connectedacross the generator circuit-and is hence responsive to fluctuations ingenerator 'voltage renders the regulator coil 37 causing a furthertilting of exceedingly sensitive during this floating condition.

7 claims.

. hereinafter employed, is intended to designate a member in a state ofequilibrium freely rockable about an axis, either hori- Under thiscondition the coil 4ft becomespractically inactive except that itresponds to slight flow therethrough in one direction or another tomaintain the floating condition. y

In some instances, it has been found desirable to reduce the generatorvoltage before the battery is full charged, as, for example, to taperofi the battery charging rate as the battery approaches a fully chargedcondition. -At such times the voltage necessar to maintain a normalcharging rate is or inari'ly' excessive for the eflicient operation ofthe work circuit. To reduce the generator voltage at such times, theswitch is closed so as to excite the coil 45." This obviously results ina further tilting action of the arm20 to increase the field resistance19 and decrease the generator volta e. By reducing the resistance 53 afurt er reduction in the generator voltage may be obtained. In this waythe battery continues to be charged, but at a lower rate, while thegenerator voltage is reduced to that appropriate for operating the workcircuit;

Various changes may be made in the embodiment of the inventionhereinabove specifically described, without departing from orsacrificing any of the advantages of the invention as defined in the apended The term balanced mem er, as,

zontal or otherwise, under the influence of a slight exciting force.

I claim:

1. In .a regulator the combination of a variable resistance, a rockablemember cooperating with said resistance to regulate t e same, meansstructurall combined with said. member to form a ba anced unit andproviding a magnetic field, and means providi'ng a variable magneticfield disposed at an an le to said first named field and impressethereon to control said unit to therey regulate said resistance.

2. a regulator the combination of .means providing a variable magneticfield,

ma etic means angularly disposed within sai field and responsive tofluctuations therein, a member structurally combined with said magneticmeans to form a balanced um't freel movable in response to saidfluctuations,

and a variable resistance controlled by said member.

3. In a regulator the combination of means roviding a variable magneticfield ma etic -means' having a field dis osed wi and substantiallynormal to sai first named field, a member structurally combined withsaidma etic means to form a balanced unit rocka 10 about an axis sub-'stantially normal to the axes of said fields in said cups.

variable resistance, a rockable member cooperating with said resistanceto regulate the same, and means comprising two relatively movableelements providing angularly disposed relatively movable magnetic fieldsreacting to control said member, one of said elements being structurallycombined with said member to form a unit balanced against the reactionsbetween said fields.

5. In a regulator the combination of a variable resistance, a memberrockable to va said resistance, means providing a variable magneticfield, and ma etic means rockable in response to variations in saidfield, said magnetic means being structurally combined with said memberto form a unit balanced against the reaction of said field on saidmagnetic means.

6. In a regulator the combination of a series of mercury cups, avariable resistance a rockable member cooperating with said cups toregulate said resistance, and means comprising two relatively movableelements providing reactin magnetic fields for controlling said mem er,one of said'elements being structurally combined to form a rock ableunit balanced against the reactions be-- tween said fields. I

7. In a regulator the combination of a series of mercury cups, a memberhaving a series of contact points depending in said cups, respectively,said member bein balanced for rocking action about a su stantiallyhorizontal axis and movable to withdraw said points successively fromcontact with the mercu in said cups, said memher being partia lysupported by the buoy ant elfect of the mercury on said points, and

means providing a pair of reacting magnetic fields for rocking said armabout the pivotal axis thereof to withdraw said points successively outof contact with the mercury 8. In a regulator the combination of aresistance, a member rockable about a fixed axis, fluid contactscontrolled by said membet" for regulating said resistance, meansproviding a magnetic field of v ing in: tensity, and an elementstructui' dliy combined with said member to form a balanced unit andprovidin a magnetic field angularly disposed wit in said first namedfield reacting to fluctuations therein to actuate said member. v

9. In a regulator the combination of .a resistance, a member mounted forfree rocking action about a fixed axis, fluid contacts controlled bysaid member for regulating said resistance, amagnetic element fixed tosaid member adjacent said axis to 'forma balanced unit, and a'fixed'electro-magnetic coil surrounding said element for actuating the same.

10. In a regulator the combination of a resistance, a member mounted forfree rocking action about a fixed axis, fluid contacts controlled bysaid member for regulating said resistance, an element fixed to saidmember adjacent said axis to form a balanced unit and providing amagnetic field substantially normal thereto, and an electromagnetic coilsurroundin said element and providing a magnetic fiel substantiallynormal to said axis and to said first named field and reacting on saidfirst named field to control the position of said member.

In witness whereof, I hereunto subscribe my name this 5th day of--April, 1924:. HARVEY TERHORST.

